function * foo1() {

	var a = yield  null ;
	console.log(`a = ${a}, 类型: ${typeof a}`);
}


function * foo2() {

	return 'hello foo2'
}
var r1 = foo1()
console.log(r1, typeof r1, Object.prototype.toString.call(r1));
console.log(r1.next(1))
console.log(r1.next('2'))

console.log('---------------------------------------------------\n');


var r2 = foo2()
console.log(r2, typeof r2, Object.prototype.toString.call(r2));
console.log(r2.next())
console.log(r2.next())


